Request for `prependTemplateDir()` or more options with `addTemplateDir()` - weight, duplicate handling

[eileenmcnaughton]

We have a code base (CiviCRM) that uses Smarty & can be extended by extensions.

Our main code base registers the template directory but the plugins can also register their own. However, in many cases the plugins want their directories to take precedence.

This is a feature request to be able to call addTemplateDir() with a weight or similar or prependTemplateDir().

A secondary request is that this would handle duplicates. We have found that calling getTemplateDirs() is expensive if done between calls to addTemplateDir() and often the extensions are unaware of each other.

[wisskid]

Could you elaborate on that second request? I'm afraid I don't understand what you mean.

[wisskid]

And as for your first request, would you need something like this?

    public function prependTemplateDir($new_template_dir, $is_config = false): void {
        $current_template_dirs = $this->getTemplateDir(null, $is_config);
        array_unshift($current_template_dirs, $new_template_dir);
        $this->setTemplateDir($current_template_dirs, $is_config);
    }

[totten]

@wisskid Yeah, that's the basic idea. Part of the reason for filing this is... that we recently found that's non-performant to repeatedly combine getTemplateDir() and setTemplateDir(). The going theory: each call to getTemplateDir() causes it to re-run normalization over all the paths.

For a small number of paths, that's fine. But it turns out - whenever one extension adds a path, it (re)normalizes n-many paths for all prior extensions. So it's basically O(n^2). Or here's the longer rationalization of that theory:

With a handful of extensions, no one notices. But for folks with a large number of extensions, it balloons.

So prependTemplateDirs() would probably want to bypass the (re)normalization that's built into getTemplateDir().

[eileenmcnaughton]

thanks for the quick reply - I was writing a response but seems Tim did first so I'll go with 'what he said' on the second.

On the first, I might be wrong on the second request but it's my understanding that if I have 2 bits of code that don't know about each other & each do

 $smarty->addTemplateDir('\srv\var\template');

Then the template will potentially be added and / or processed through _realPath() twice. I kinda get that it needs to be for symlinks but maybe there is a cheap check that can be done before going through all the expensive stuff

[wisskid]

I see. In that case, we can change it as follows:

    public function prependTemplateDir($new_template_dir, $is_config = false): void {
        $current_template_dirs = $is_config ? $this->config_dir : $this->template_dir;
        array_unshift($current_template_dirs, $new_template_dir);
        $this->setTemplateDir($current_template_dirs, $is_config);
    }

That would postpone the expensive call to _normalizeTemplateConfig up until the first load of a template. Correct?

[eileenmcnaughton]

Yes that seems correct to me

[wisskid]

I'll try to squeeze it in asap

[eileenmcnaughton]

thank you - you have been incredibly responsive!

[wisskid]

@eileenmcnaughton you're welcome!